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Won't everything expand at the same rate and the lash will remain constant?
Hi Peter...what difference in sound or performance are you noticing with these new gears? When you say tight, do you mean the bike feels restricted in performance, or just tighter as in you're breaking in a new engine?Cheers
Have you discussed this with Mr. Caruso? Paul B.
I have a set of Caruso timing gears that I fitted to my Norge.Here is an imageQuestion is..I consider the lash between the crank and cam gears to be absolute minimum. What is the consensus regarding this lash ?Will it increase or decrease when hot ? My educated guess is that the cases will expand when at operating temp, resulting in them “growing apart” a very small amount, thus increasing the lash. But that is only a guess, does anyone have an educated opinion ?I would like to hear from Tusayan as well as anyone else.
I have these fitted to a few engines. The tooth clearance will increase as the engine cases get to operating temp.Ciao
Because I knew there is zero lash in the pair and mindful of the torture that I would be inflicting if they got any tighter, I did not know if the sound was normal.I was expecting a whirring sound, but this was more of a subdued scream. I re installed the chain, out of an abundance of caution.
Wise to halt at zero clearance, Keep us updated
precisely the reason there is a determined clearance between gear tip and root of its mate.
Wouldn't Plastigage pretty much do the same thing? kk
Did Mr. Caruso mention if the gears tend to quiet down after they are run in for a while? Rick.
Huzo,I have this exact same set of gears in my Breva right now and can attest to your concern about the sound. For me it was a pleasant change from the tappity-tap-tap cacophony emanating from the left side as my original chain tensioner was complete junk. The sound was replaced by a substantially quieter whirr of the straight cut gears. If I recall you have already upgraded your tensioner and I presume your motor didn't suffer from the calamity of noise that mine had. In my humble opinion, as long as you can smoothly turn the motor over by hand with the plugs out then I trust the quality of Joe Caruso's workmanship.I have several thousand miles on mine since installed and all is well.Skippy
Guissepe Caruso went on to point this out.Although I don’t think it applies in this case, it is possible to attempt to discern the lash between the crank and cam gear pairing and find none.This can be because there is none.OrThe reluctance for the cam gear to turn by hand pressure due to the frictional drag and the loading of the rockers against the lobes. It will feel like the gears have zero lash and are solidly meshing, when in fact they are not.The go is, to fit them on their shafts and leave the driving pin out of the camwheel and see if any lash exists.I’m fitting a new oil pump when I get back from Italy with the Norge and I’ll investigate it then.
And so the plot thickens!Perhaps a more appropriate title would be , how do you measure lash ?Assumption got answers other than one you wanted.Personally, I fit gears for (permanent) accurate valve timing as much as for reduced reciprocating mass, usually with a new camshaft.So, rockers off, dial gauges on pushrods, degree wheel on crank, fit pin in appropriate hole on predrilled cam gear.Original loopy camshaft gears came predrilled like this, I made a jig 40 years ago to do same, 5 holes not one, surprising that these gears are not drilled, perhaps because he originally intended them for Daytona engines which have vernier adjustment at camshaft/pulley. Carcano designed pushrod motor was always intended to have the adjustment at cam gear, original workshop manual shows you how to fit and set up gears.My 1967 V700 on factory painted marks was 1 degree advanced from Carcano’s figures, I guess every motor was timed by hand then, marks painted by tradesman.I still do it that wayWithout rockers, lash is easily felt and valve timing accurately adjusted (+ or - 1 degree is pretty good for a factory build imho, interesting how your Norge with a few miles and aftermarket gears times up.Peak lift angle and overlap in and ex at tdc tell you everything, very light (carb) valve springs installed for final check.
Journeyman Tool & Die maker here and I couldn't feel 0.002" lash in the gears when I set up the alternator drive on my Ural. It required a dial indicator on a tooth face for me to get true proof of movement.Of course I was the other side of 68 then. Might make a difference?